Low maternal vitamin D is associated with increased risk of congenital and peri/postnatal transmission of Cytomegalovirus in women with HIV

Background

CMV infection of the fetus or neonate can lead to devastating disease, and there are no effective prevention strategies to date. Vitamin D is a potent immunomodulator, supports antiviral immune responses, and plays an important role in placental immunity.

Methods

Retrospective cohort study to evaluate the impact of low maternal vitamin D on congenital and early postnatal transmission of CMV among HIV-infected, non-breastfeeding women and their HIV exposed but negative infants from an urban HIV clinic. Vitamin D panel was performed on stored maternal plasma obtained near time of delivery. Infant CMV testing at 0–6 months included urine and oral cultures, and/or serum polymerase chain reaction testing.

Results

Cohort included 340 mother-infant pairs (births 1991–2014). Among 38 infants (11%) with a CMV+ test between 0–6 months, 4.7% (14/300) had congenital CMV transmission (CMV+ test 0–3 weeks), and 7.6% (24/315) had peri/postnatal CMV (CMV+ test >3 weeks-6 months). Women with lower calcitriol (1,25-dihydroxyvitamin D), the active form of vitamin D, were more likely to have an infant with congenital (OR 12.2 [95% CI 1.61–92.2] P = 0.02) and peri/postnatal (OR 9.84 [95% CI 2.63–36.8] P = 0.0007) infections in multivariate analyses, independent of maternal HIV viral load and CD4 count.

Conclusion

This study demonstrates an association between inadequate maternal calcitriol during pregnancy and increased congenital and early postnatal acquisition of CMV among non-breastfeeding women with HIV and their HIV negative infants.

429 Right ventricular longitudinal and radial fiber contractility in patients undergoing mitral valve surgery: a PREPARE-MVR substudy

Severe mitral regurgitation results in significant hemodynamic demands of not only the left, but the right ventricle (RV) as well. Increased pulmonary pressures and consequential pressure overload of the RV induces complex remodeling, which can be partially restored by mitral valve repair/replacement (MVR). MVR is associated with marked changes of RV deformation, however, the clinical significance of these changes is not well estabilished. The PREPARE-MVR study (PRediction of Early PostoperAtive Right vEntricular failure in Mitral Valve Replacement/Repair patients) aims to determine parameters, which may predict the perioperative risk of acute RV failure.

In this current substudy, our aim was to determine the changes of RV global, longitudinal and radial fiber contractility before and following MVR.

Our study group consisted of 27 MVR patients (mean age: 64 ± 12 years, m/f: 19/8). Transthoracic 3D echocardiography was performed before the operation and following intensive care unit discharge. 3D beutel model of the RV was created and RV end-diastolic volume index (EDVi) among with RV ejection fraction (RVEF) were calculated using commercially available software. For in-depth analysis of RV mechanics, we have decomposed the motion of the RV using our custom software (ReVISION) to determine longitudinal (LEF) and radial ejection fraction (REF). Right heart catheterization was also performed before MVR and 24 hours after MVR as well to measure pulmonary arterial mean systolic pressure (mPAP), pulmonary arterial wedge pressure (PAWP) and RV stroke work index (RVSWi). Using the aforementioned parameters, we have calculated RV longitudinal (longRVSWi) and RV radial stroke work index (radRVSWi), which represent RV longitudinal and radial fiber contractility.

RV morphology did not change significantly according to RVEDVi (preop vs. postop: 71 ± 17 vs. 72 ± 20 mL/m², p = NS). RVEF slightly decreased after MVR (50 ± 6 vs. 48 ± 7 %, p < 0.05), however, RV motion pattern markedly changed. Postoperative LEF was significantly lower compared to preoperative values (25 ± 6 vs. 16 ± 6%, p < 0.0001), among with an increase in REF (21 ± 7 vs. 27 ± 7%, p < 0.01). As expected, mPAP and PAWP decreased in response to MVR (mPAP: 30 ± 10 vs. 25 ± 7 mmHg; PAWP: 19 ± 7 vs. 13 ± 3 mmHg, both p < 0.01). Global RV contractility decreased after surgery (RVSWi: 603 ± 355 vs. 474 ± 251 mmHg*mL/m², p < 0.05). While RV longitudinal contractility also significantly reduced (longRVSWi: 289 ± 179 vs. 166 ± 122 mmHg*mL/m², p < 0.001), radial contractility was maintained following MVR (radRVSWi: 240 ± 141 vs. 261 ± 144 mmHg*mL/m², p = NS).

MVR is associated with marked changes of RV function and hemodynamics. RV longitudinal and radial contractility have distinct response to surgery, which may be important in postoperative patient management. The PREPARE-MVR study aims to examine the role of preoperative RV mechanics in clinical outcome.

P947 Left- and right ventricular mechanics in athletes: a true marker of fitness?

Regular physical exercise results in marked changes of ventricular morphology and function, also referred as the athlete’s heart. Despite the marked changes of cardiac morphology and function in athletes, data is scarce regarding the relationship between exercise performance and cardiac adaptation to exercise.

Accordingly, our aim was to examine the relationship between ventricular morphology and function and exercise capacity in a prospective cohort study.

Young elite soccer players (n = 18, age: 16 ± 1 years) were enrolled and examined at baseline and following 1 year. Athletes underwent cardiopulmonary exercise testing to determine peak oxygen uptake (VO2/kg). Following exercise testing, 3D echocardiography was performed and LV and RV focused loops were obtained. By off-line analysis, we measured left- (LV) and right ventricular (RV) end-diastolic volume indices (EDVi) and LV mass index (LVMi) indexed to body surface area and LV and RV ejection fractions (EF). By 3D speckle-tracking analysis of the LV and RV we also determined global longitudinal (GLS) and circumferential (GCS) strains.

We found improved and decreased peak exercise performance as well during the 1 year follow-up with an overrall increased mean exercise capacity (dVO2/kg: 2.6 ± 7.3 ml/min/kg). LV and RV morphology did not change significantly according to LVEDVi and RVEDVi (LVEDVi: 84 ± 14 vs. 80 ± 7 ml/ m², RVEDVi: 82 ± 11 vs. 84 ± 10 ml/m², both p = NS). LVMi significantly increased (82 ± 14 vs. 89 ± 9 g/m², p < 0.001). LV and RV EF did not change during one year follow-up (LVEF: 58 ± 4 vs. 57 ± 5%; RVEF: 57 ± 4 vs. 55 ± 6%, both p = NS), while LVGLS decreased compared to baseline (19.7 ± 1,8 vs. 19.3 ± 2,8%, p < 0.01). The change in VO2/kg showed correlation with decreased LVGLS and also with decreased RVGCS (dLVGLS vs. dVO2/kg: r=-0.56, dRVGCS vs. dVO2/kg: r=-0.50, both p < 0.05)

During 1 year follow-up cardiac morphology and function significantly changed in our athlete cohort, and these changes showed relationship with the changes of peak exercise performance. Detailed assessment of myocardial mechanics may help to monitor training in athletes.

646. Evaluation of the Utility of a New Comprehensive Molecular Assay to Test for the Common Pathogens that Cause Lower Respiratory Tract Infections and its Potential Impact on Antibiotic Therapy

Background

Lower respiratory tract infection (LRTI) has high mortality among critically ill patients. The current standard of care for diagnosing bacterial causes of LRTI is respiratory culture, which is time consuming and insensitive. The FilmArray Pneumonia Panel (FA-Pneumo) (Biofire Diagnostics, Salt Lake City, UT) is FDA-cleared for the detection of lower respiratory tract pathogens (bacteria, atypical bacteria, and viruses) directly from lower respiratory tract specimens. Here, we evaluated the performance of the FA-Pneumo assay in bronchoalveolar lavage (BAL) samples and assessed its potential impact on antibiotic therapy.

Methods

A total of 61 BAL samples collected for respiratory culture from intensive care unit patients aged 18 years and older who had symptoms consistent with LRTI were included in the study. Remnant BAL samples were tested using the FA-Pneumo and results were compared with standard of care respiratory culture results. We then conducted a chart review to determine the potential impact of FA-Pneumo results on antibiotic therapy.

Results

The results of 48 out of 61 BAL samples (78.7%) were the same when comparing FA-Pneumo with a standard of care respiratory culture. Two patients grew Stenotrophomonas maltophilia and 1 patient grew Achromobacter. Importantly, neither of these organisms is targeted by the FA-Pneumo assay. Three patients (4.9%) had viral LRTI, with 9 patients (14.8%) having bacterial/viral co-infection. A total of six patients with methicillin-susceptible Staphylococcus aureus (MSSA) remained on vancomycin therapy for a median of 1.5 days (range 0–7 days) and all three patients with viral LRTI remained on broad-spectrum antibiotic therapy for a median of 4 days (range 3–13 days). All three patients with ESBL-positive Enterobacteriaceae detected by FA-Pneumo and culture were not started on appropriate antibiotic therapy until >48 hours after the FA-Pneumo would have been resulted.

Conclusion

The FA-Pneumo assay has the potential to lead to earlier discontinuation of vancomycin for patients with MSSA LRTI and earlier broadening of therapy for ESBL LRTI. Providers should be aware of the inability of the FA-Pneumo to detect S. maltophilia and Achromobacter species.

Disclosures

All authors: No reported disclosures.

P3105Cardiopulmonary exercise testing normal values for young athletes and non-athletes

Introduction

Cardiopulmonary exercise testing (CPET) is an important diagnostic method to evaluate athletes and non-athletes, however we do not have widely accepted normal values for correct evaluation and interpretation in the young.

Goals

Our aim was to compare CPET parameters of young athletes and non-athletes and determine reference values.

Methods

Exercise tests were performed in young non-athletes, aged <18 years between 2011 to 2016 at Mayo Clinic. Athletes underwent detailed sports cardiology screening including CPET at Semmelweis University Heart and Vascular Center between 2016 and 2018. Individuals with cardiovascular disease were excluded. We created 2 subgroups in both sexes: 12–14 years (Group 1), 15–17 years (Group 2). Statistical analysis was performed using SAS with analysis of variance under the general linear model adjusting for age, body mass index and test effort based on peak respiratory exchange ratio (RER).

Results

A total of 212 athletes (92% male, 15.5±0.6ys) and 207 non-athletes (68% male, 15.0±0.7ys) were included in the analysis. In Group 1 boys, athletes have higher peak HR (200.0±9.2 vs 188.5±16.8 bpm, p<0.0001), HR reserve (117.1±14.5 vs 108.9±19.8 bpm p<0.05), VO2 max (53.7±6.6 vs 44.7±9.1 mL/kg/min p<0.0001), ventilation (VE) (120.3±25.0 vs 70.7±21.6 L/min p<0.0001) and RER (1.12±0.0 vs 1.07±0.08, p <.001) compared to controls. In Group 2 boys, there was no difference in peak HR and HR reserve, but athletes have higher VO2 max (57.2±4.7 vs 45.3±9.3 mL/kg/min, p<0.0001) and VE (150.7±23.7 vs 104.1±25.9 L/min, p<0.0001), similarly as Group 2 girls: VO2 max (46.3±3.6 vs 34.9±8.5 mL/kg/min p<0.0001), VE (118.7±12.5 vs 68.4±20.6 L/min, p<0.0001). In male athletes, peak HR (200.6±9.2 vs 196.5±7.4 bpm p<0.05) and HR recovery (34.2±9.8 vs 29.8±11.1 bpm p<0.05) decreases with age, while VO2 max (53.7±6.6 vs 57.2±4.7 mL/kg/min, p<0.001) and VE (120.3±24.9 vs 150.7±23.7 L/min, p<0.0001) increases. Lower cut-off values were determined in each group (Figure).

Lower-cut off values

Conclusion

We created a unique Mayo-Semmelweis database of young athletes and non-athletes. As a result of intensive training, athletes show higher levels of CPET variables vs non-athletes. Our study provides CPET reference values in the pediatric age group, applying them could contribute to correct evaluation and interpretation of CPET, increasing its diagnostic potential.

P3445Subclinical myocardial dysfunction in pediatric kidney transplant recipients: a two-dimensional speckle-tracking echocardiography study

Chronic kidney disease is associated with increased risk of cardiovascular mortality and morbidity in pediatric patients as well. Renal transplantation results in improved survival, however, several factors contribute to markedly elevated cardiovascular complication rate compared to the healthy population. While major cardiac events occur rarely in pediatric population, detection of subclinical changes in cardiac morphology and function may be of high interest to effectively identify high-risk patients.

Accordingly, our aim was to investigate left (LV)- and right ventricular (RV) morphology and function using conventional and two-dimensional (2D) speckle-tracking echocardiography (STE) in pediatric renal transplant recipients.

Our study group consisted of 41 kidney transplanted children (RTX; mean age: 14±3 years, m/f: 25/16) and 39 age- and gender matched healthy controls. Using 2D echocardiography, LV and RV focused apical loops were obtained and LV end-diastolic volume index (EDVi), ejection fraction (EF), mass index (Mi), RV end-diastolic area index (EDAi) and fractional area change (FAC) were measured. Using STE, we have determined LV global longitudinal (GLS) and circumferential strain (GCS), RV GLS, and LV and RV early diastolic longitudinal strain rate (LSrE).

LV EDVi did not differ between RTX and controls (51±13 vs. 52±10 mL/m2, p=NS), while LVMi was markedly higher in RTX patients (36±8 vs. 28±6 g/m2, p<0.0001). LVEF was comparable between the two groups (62±5 vs. 62±3%; p=NS), while LV GLS was significantly lower in RTX (−20.6±2.1 vs. −21.8±2.1%, p=0.01) along with a tendential increase in LV GCS (−31.6±4.3 vs. −29.7±4.6%, p=0.06). LV LSrE was significantly lower in RTX patients (1.29±0.29 vs. 1.45±0.27 1/s, p<0.05). RV EDAi did not differ between the two groups (11.2±2.3 vs. 11.6±2.0 cm2/m2, p=NS). Interestingly however, RTX patients had significantly higher RV FAC and RV GLS (FAC: 46±7 vs. 42±4%, GLS: −24.6±3.7 vs. −22.4±2.6%, both p<0.01) along with lower RV LSrE (1.32±0.57 vs. 1.60±0.43, p<0.05).

Cardiac morphology and function shows distinct changes after RTX. Along with comparable ventricular dimensions, LV hypertrophy and subclinical systolic and diastolic dysfunction is present. RV systolic function is relatively increased accompanied by subclinical diastolic dysfunction of the chamber, which may refer to previous RV overload. STE may be a useful tool to reveal early myocardial dysfunction in pediatric kidney transplant recipients.

5107Survival prediction in patients undergoing cardiac resynchronization therapy: a machine learning based risk stratification system

Background

Cardiac Resynchronization Therapy (CRT) has well-known beneficial effects in patients with advanced heart failure, reduced ejection fraction and wide QRS complex. However, mortality rates still remain high in this patient population. Therefore, precise risk stratification would be essential, nonetheless, the currently available risk scores have several shortcomings which hamper their utilization in the everyday clinical practice.

Purpose

Accordingly, our objective was to design and validate a machine learning based risk stratification system to predict 2-year and 5-year mortality from pre-implant parameters of patients undergoing CRT implantation.

Methods

We trained two models separately to predict 2-year (model 1) and 5-year mortality (model 2). As training cohort of model 1 we used 1678 patients (67±10 years, 1251 [75%] males) undergoing CRT implantation. From this population, 1320 patients (66±10 years, 1005 [76%] males) also completed 5-year follow-up and they served as the training cohort for model 2. Forty-seven pre-implant parameters (demographics, cardiovascular risk factors and clinical characteristics) were used to train the models. Our models were designed in a way to tolerate missing values. Among non-linear classifiers, random forest demonstrated the best performance. We validated our models, along with the Seattle Heart Failure Model (SHFM), VALID-CRT risk score and EAARN score on an independent cohort of 136 patients (66±10 years, 110 [81%] males). Based on the predicted probability of survival, patients were split into quartiles and survival was plotted via Kaplan-Meier (KM) curves.

Results

There were 358 (21%) deaths in the 2-year, 697 (53%) deaths in the 5-year training cohort. In the validation cohort, there were 30 (22%) deaths at 2 years and 58 (43%) deaths at 5 years after CRT implantation. For the prediction of 2-year mortality, the Area Under the Receiver-Operating Characteristic Curve (AUC) for model 1 was 0.77 (95% CI: 0.67–0.87; p=0.002), for SHFM was 0.54 (95% CI: 0.39–0.69; p=0.006), for EAARN was 0.57 (95% CI: 0.46–0.68, p=0.002), and for VALID-CRT was 0.62 (95% CI: 0.52–0.71; p=0.002). To predict 5-year mortality, the AUC for model 2 was 0.85 (95% CI: 0.78–0.91; p=0.001), for SHFM was 0.62 (95% CI: 0.51–0.74; p=0.003), for EAARN was 0.61 (95% CI: 0.51–0.70, p=0.002), for VALID-CRT was 0.65 (95% CI: 0.56–0.74; p=0.002). The AUCs of the machine learning based models were significantly higher than the AUCs of the pre-existing scores (DeLong test, all p<0.05). The KM curves of the quartiles were significantly separating in both models (Log-rank test, both p<0.001).

Conclusion

Our results indicate that machine learning algorithms can outperform the already existing linear model based scores. By capturing the non-linear association of predictors, the utilization of these state-of-the-art approaches may facilitate optimal candidate selection and prognostication of patients undergoing CRT implantation.

5939Perioperative shift in right ventricular mechanical pattern in patients undergoing mitral valve surgery: a predictor of right ventricular failure?

Background

Severe mitral regurgitation (MR) induces significant changes not only in the left, but also in the right ventricular (RV) morphology and function. Early treatment of MR is recommended, however, surgical procedure disrupts the native RV contractile pattern and predisposes the at-risk ventricle to develop postoperative RV failure (RVF) which is associated with poor outcomes.

Purpose

Accordingly, the PREPARE-MVR study (PRediction of Early PostoperAtive Right vEntricular failure in Mitral Valve Replacement/Repair patients) aims to explore the alterations of RV contraction pattern in patients undergoing MVR and to investigate the association of preoperative echocardiographic findings with early postoperative RVF.

Methods

We prospectively enrolled 70 patients (62±12 years, 67% males) undergoing open heart MVR. Thirty age and gender matched healthy volunteers served as control group. Transthoracic 3D echocardiography was performed preoperatively and at intensive care unit discharge. Furthermore, focused 2D echocardiogram was also obtained during the ICU stay. Forty-three patients also completed 6 months follow-up. 3D model of the RV was reconstructed and end-diastolic volume index (EDVi) along with RV ejection fraction (RVEF) were calculated. For in-depth analysis of RV mechanics, we decomposed the motion of the RV to compute longitudinal (LEF) and radial ejection fraction (REF). Right heart catheterization was performed to monitor RV stroke work index (RVSWi).

Results

RV morphology as assessed by EDVi was unaffected by surgery (preoperative vs postoperative; 73±17 vs 71±16 mL/m2, p=NS). RVEF was slightly decreased after MVR (52±6 vs 48±7%, p<0.05), whereas RV contraction pattern has changed notably. Before MVR, the longitudinal shortening was the main contributor to global systolic function (LEF/RVEF vs REF/RVEF; 0.53±0.10 vs 0.43±0.12; p<0.001), whereas in controls the longitudinal and radial shortening contributed equally to RVEF (0.47±0.07 vs 0.43±0.09; p=NS). Postoperatively, the radial motion became dominant (0.35±0.08 vs 0.47±0.09; p<0.001). However, this shift was only temporary as 6 months later the contraction pattern became similar to controls showing equal contribution of the two components (0.44±0.10 vs 0.42±0.11; p=NS). Postoperative RVF (defined as RVSWi <300 mmHg*mL/m2 or ICU TAPSE <10 mm) was detected in 14 [20%] patients. Preoperative LEF was associated with postoperative RVSWi (r=−0.61, p<0.001) and it was an independent predictor of postoperative RVF (OR=1.16 [1.03–1.35], p<0.05).

Conclusion

Severe MR induces a significant shift in the RV mechanical pattern which may influence the development of postoperative RV dysfunction and failure after MVR. Advanced indices of RV mechanics are associated with invasively measured parameters of RV contractility and may predict postoperative RVF.

P310Differentiation between arrhythmogenic right ventricular cardiomyopathy and athlete's heart using cardiac magnetic resonance based derived parameters and strain analysis

Acknowledgement/Funding

National Research, Development and Innovation Office (NKFIH) of Hungary (K 120277), ÚNKP-18-3-IV New National Excellence Program of Human Capacities.

6066Equal significance of longitudinal and radial wall motion represents the normal right ventricular mechanical pattern: 3D echocardiographic study in 231 healthy volunteers

Three main mechanisms contribute to right ventricular (RV) pump function: (1) shortening of the longitudinal axis with traction of the tricuspid annulus towards the apex; (2) inward (radial) movement of the RV free wall, which is often referred as the “bellows effect”; and (3) bulging of the interventricular septum into the RV during the left ventricular contraction and stretching of the free wall over the septum (causing shortening in the anteroposterior direction). Despite the established clinical value of the functional changes among the aforementioned components, their relative importance remains to be quantified during physiological conditions.

Accordingly, the aim of our study was to evaluate the relative contribution of the different RV motion directions to global RV function on both global and segmental level in a large set of healthy individuals.

We have recruited 231 healthy volunteers (44% female, with a wide and balanced age range from 8 to 81 years) from two experienced centers performing transthoracic 3D echocardiography (3DE) on a routine basis. 3DE datasets focused on the RV were obtained using multi-beat acquisition. We determined RV volumes and subsequent ejection fraction (RVEF) by dedicated software. Using the ReVISION method, we have decomposed the motion of the RV to determine longitudinal (LEF), radial (REF) and anteroposterior ejection fraction (AEF). Their ratio to RVEF quantifies the relative contribution of the given component to global RV function. Moreover, regional subvolumes were also analyzed in a 15-segment model.

Mean value of RVEF was significantly higher in female subjects compared to male subjects (60±7 vs. 56±7%, p<0.001). The relative contributions of LEF and REF to RVEF were comparable, while the contribution of AEF was significantly lower (LEF/RVEF vs. REF/RVEF vs. AEF/RVEF: 0.48±0.08 vs. 0.49±0.07 vs. 0.39±0.11, p<0.001) in the pooled population as well as in the genders separately. In line with higher RVEF found in women, female gender was associated with a higher longitudinal and radial contribution compared to males, however, AEF was similar (women vs. men; LEF/RVEF: 0.49±0.08 vs. 0.47±0.07, p<0.05; REF/RVEF: 0.50±0.07 vs. 0.48±0.06, p<0.01; AEF/RVEF: 0.38±0.12 vs. 0.40±0.10, p=NS). Interestingly, AEF/RVEF showed a significant deterioration with age (r=−0.354, p<0.001), while age-dependency of the longitudinal and radial contributions were not observed concerning both genders. An age-related decrease could be demonstrated by the volume fractions of the 5 septal volumetric segments (r=−0.229, p<0.001).

Motion decomposition and the 15 segments

In physiological conditions, the relative importance of longitudinal and radial wall motions is similar in determining global RV function. Aging accompanied by a decrease in anteroposterior shortening, which may point to a deteriorating systolic LV-RV interaction. Our results may facilitate further research concerning the alterations of RV mechanical pattern in various disease states.

P1631Machine-learning defined predictors of mortality in ischemic and non-ischemic heart failure patients undergoing CRT-P or CRT-D implantation

Background

Both Cardiac Resynchronization Therapy Pacemakers (CRT-P) and CRT Defibrillators (CRT-D) improve mortality in heart failure patients with reduced ejection fraction and wide QRS complex. However, not every patient benefits equally from each type of treatment and determinants of mortality may vary across the subgroups of patients with different etiologies and devices.

Purpose

Our aim was to investigate the differences in the predictors of long-term mortality in heart failure patients with different etiologies undergoing CRT-P or CRT-D implantation using machine learning.

Methods

We created 4 separate random forest models to predict 5-year all-cause mortality (models for ischemic and non-ischemic etiology in both CRT-P and CRT-D subgroups). A registry of 1650 patients (66±10 years, 1258 [76%] males, 751 [46%] CRT-D) was used as the training cohort for the prediction models. Forty-seven pre-implant parameters including cardiovascular risk factors and clinical variables were utilized to train our models. For each clinical parameter, we calculated the mean decrease in Gini impurity (dG). Based on the extent of decline, the 10 most important features were selected for each model. To keep the data comparable between the different models, we took the union of these features and plotted the results on radar charts.

Results

There were 879 (53%) deaths during the follow-up period. The mortality benefit of adding an Implantable Cardioverter Defibrillator could be observed only in ischemic patients (Hazard Ratio = 0.83, 95% Confidence Interval: 0.72–0.97, p<0.005), but not in the entire cohort or in patients with non-ischemic etiology. In patients with non-ischemic etiology, the pattern of mortality predictors were almost similar: in CRT-P patients the most important predictors were age, serum urea levels and left ventricular ejection fraction (LVEF) (dG: 0.114, 0.054 and 0.053, respectively) whereas in the CRT-D subgroup these factors were age, LVEF and serum sodium (dG: 0.116, 0.060 and 0.052, respectively). In CRT-P patients with non-ischemic etiology, the most relevant variables were age serum urea and LVEF in decreasing order (dG: 0.085, 0.060 and 0.050, respectively). The strongest predictors of mortality were age, hemoglobin and serum creatinine in ischemic patients with CRT-D (dG: 0.088, 0.060 and 0.052, respectively).

CRT-P vs. CRT-D by ischemic etiology

Conclusions

In patients with ischemic heart failure, CRT-D was associated with a mortality benefit compared to CRT-P. Our results also suggest that machine-learning may identify distinct patterns in clinical characteristics for a better mortality prediction. Taking these factors into consideration during the management of heart failure patients with CRT, risk stratification and outcomes could be improved.

Magnetic properties of artificially designed magnetic stray field landscapes in laterally confined exchange-bias layers

Magnetic stray fields generated by domain walls (DWs) have attracted significant attention as they might be employed for precise positioning and active control of micro- and nano-sized magnetic objects in fluids or in the field of magnonics. The presented work intends to investigate the near-field response of magnetic stray field landscapes above generic types of charged DWs as occurring in thin films with in-plane anisotropy and preferential formation of Néel type DWs when disturbed by external magnetic fields. For this purpose, artificial magnetic stripe domain patterns with three defined domain configurations, i.e. head-to-head (tail-to-tail), head-to-side, and side-by-side, were fabricated via ion bombardment induced magnetic patterning of an exchange-biased IrMn/CoFe bilayer. The magnetic stray field landscapes as well as the local magnetization reversal of the various domain configurations were analyzed in an external magnetic field by scanning magnetoresistive microscopy and compared to micromagnetic simulations.

Abstract P1-01-04: Mutational profiling of breast cancer brain metastases – matched pair analysis of next generation sequencing between primary breast cancer and later developed brain metastases

Background: Despite increased survival in patients with advanced breast cancer, breast cancer brain metastases (BCBM), remains a final frontier with a mean survival of 3-12 months. The biology facilitating BCBM is not fully understood.

Aims: To compare gene expression profiles in primary BC, and later diagnosed, surgically removed BCBM.

Material and Methods: A total of 58 BCBM and 46 breast tumors were analyzed with next generation sequencing (NGS). DNA was isolated from FFPE sectionsand then the Cancer Hotspot Panel v2 (ThermoFisher Scientific) covering 207-targeted regions in 50 cancer related genes was used. Template preparation and enrichment were performed with the IonChefTM Instrument (ThermoFisher Scientific). Eight barcoded samples were pooled per Ion 318 TM v2 BC chip and sequenced on the Ion PGMTM System (ThermoFisher Scientific).Alignment to the hg19 human reference genome and variant calling was performed by the Torrent Suite Software v5.2.0 (ThermoFisher Scientific) also IonReporterTM System (ThermoFisher Scientific) was used.

Results: 46 of the BCBM were matched with a primary breast cancer tumor. All but 12 tumors had the same IHC characteristic in the matched pairs. The most common transformation was Luminal A to Luminal B in 8 tumors. The other changes were triple negative subtype (TNBC) to Luminal B, HER2+ to Luminal B, Luminal A to TNBC and Luminal A to HER2+ with one case respectively. The BCBM had the following IHC profile: one tumor was luminal A (1%), 15 tumors were Luminal B (25%), 29 were TNBC (50%) and 14 HER2 overexpressing (24%). The preliminary NGS data shows that the most common mutation in BCBM was found in the tumor suppressor gene p53 (22/58, 38 %). Other common mutations were PIK3CA (17/58, 29%); KDR (16/58, 28%), KIT (9/58, 16%) and PTEN (2/58, 3%). The corresponding figures in the primary BC were p53 (15/46, 33%), PIK3CA (16/46, 35%), KDR (17/46, 37%), KIT (7/46, 15%) and no tumors with PTEN. The mutational spectra in the 50 cancer related genes were similar in the primary BC as in the BCBM with 1-5 different driver mutations but additional mutations were registered in 6/46 matched cases (13%). We fail to identify any specific differences in mutations between the different morphological subtypes (LumA/LumB/TNBC/HER2+) in the metastatic sample. In the NGS analysis of the metastases and primary tumors 3 different variations of p53 was detected.

Conclusions: In this large matched pairs of primary breast tumors and BCBM we show that the majority of BCBM have a similar gene profile as the primary BC. The most common aberrations were found in TP53, PIK3CA and KDR. Additional post analyses are under investigation and will be added to the results. It appears that brain metastases are not different from other metastases in that they remain fairly stable in their driver mutational profile. When the mutational profile changes there is addition of mutation rather than deletion. A clinical implication of these results could be to treat BCBM according to the mutational profile of the primary tumor which decreases the need for sampling of BCBM; something that if the patient is not eligible for surgery might otherwise prove complex.

Citation Format: Thulin A, Andersson C, Werner Rönnerman E, De Lara S, Chamalidou C, Schoenfeld A, Kovacs A, Enlund F, Linderholm BK. Mutational profiling of breast cancer brain metastases – matched pair analysis of next generation sequencing between primary breast cancer and later developed brain metastases [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-01-04.

Disturbed spermatogenic signaling in pituitary adenylate cyclase activating polypeptide-deficient mice

PACAP is a neuropeptide with diverse functions in various organs, including reproductive system. It is present in the testis in high concentrations, and in addition to the stage-specific expression within the seminiferous tubules, PACAP affects spermatogenesis and the functions of Leydig and Sertoli cells. Mice lacking endogenous PACAP show reduced fertility, but the possibility of abnormalities in spermatogenic signaling has not yet been investigated. Therefore, we performed a detailed morphological analysis of spermatozoa, sperm motility and investigated signaling pathways that play a role during spermatogenesis in knockout mice. No significant alterations were found in testicular morphology or motility of sperm in homozygous and heterozygous PACAP-deficient mice in spite of the moderately increased number of severely damaged sperms. However, we found robust changes in mRNA and/or protein expression of several factors that play an important role in spermatogenesis. Protein kinase A expression was markedly reduced, while downstream phospho-ERK and p38 were elevated in knockout animals. Expression of major transcription factors, such as Sox9 and phospho-Sox9, was decreased, while that of Sox10, as a redundant factor, was increased in PACAP-deficient mice. The reduced phospho-Sox9 expression was partly due to increased expression and activity of phosphatase PP2A in knockout mice. Targets of Sox transcription factors, such as collagen type IV, were reduced in knockout mice. In summary, our results show that lack of PACAP leads to disturbed signaling in spermatogenesis, which could be a factor responsible for reduced fertility in PACAP knockout mice, and further support the role of PACAP in reproduction.